Picture frame



FIG. 1 is a front and right side perspective view of my new design for a picture frame;

FIG. 2 is a front elevated view thereof;

FIG. 3 is a rear elevated side view thereof;

FIG. 4 is a right side elevated view thereof;

FIG. 5 is a left side elevated view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a picture frame, as shown and described. 